package com.sciencep.pro.common.utils;

import org.springframework.util.CollectionUtils;

import java.util.*;


public final class CollectionUtil extends CollectionUtils {

    /**
     * 不允许实例化
     */
    private CollectionUtil() {
    }


    public static boolean isNotEmpty(Collection<?> collection) {
        return !isEmpty(collection);
    }

    public static boolean isNotEmpty(Map<?, ?> map) {
        return !isEmpty(map);
    }

    /**
     * 获取两个集合的不同元素
     *
     * @param collmax
     * @param collmin
     * @return
     */
    @SuppressWarnings({"rawtypes", "unchecked"})
    public static Collection getDifferent(Collection collmax, Collection collmin) {


        //使用LinkeList防止差异过大时,元素拷贝
        Collection csReturn = new LinkedList();
        Collection max = collmax;
        Collection min = collmin;
        //先比较大小,这样会减少后续map的if判断次数
        if (collmax.size() < collmin.size()) {
            max = collmin;
            min = collmax;
        }
        //直接指定大小,防止再散列
        Map<Object, Integer> map = new HashMap<>(max.size());
        for (Object object : max) {
            map.put(object, 1);
        }
        for (Object object : min) {
            if (map.get(object) == null) {
                csReturn.add(object);
            } else {
                map.put(object, 2);
            }
        }
        for (Map.Entry<Object, Integer> entry : map.entrySet()) {
            if (entry.getValue() == 1) {
                csReturn.add(entry.getKey());
            }
        }
        return csReturn;
    }

    /**
     * 获取两个集合的不同元素,去除重复
     *
     * @param collmax
     * @param collmin
     * @return
     */
    @SuppressWarnings({"rawtypes", "unchecked"})
    public static Collection getDifferentNoDuplicate(Collection collmax, Collection collmin) {
        return new HashSet(getDifferent(collmax, collmin));
    }


}